A Ca2+‐dependent protein kinase phosphorylates phosphoenolpyruvate carboxylase in maize

[摘要]

In C₄ plants the activity of phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) is regulated by phosphorylation/dephosphorylation which is mediated by light/dark signals. The study using protein kinase inhibitors showed that the inhibition pattern of maize PEPC-protein kinase (PEPC-PK) is similar to that of myosin light chain kinase, a Ca²⁺-calmodulin-dependent PK. The kinase activity was also inhibited by EGTA and the inhibition was relieved by Ca²⁺. These results suggest that PEPC-PK is Ca²⁺-dependent in contrast with previous observations by other research groups.

[学科分类] 生物化学/生物物理

[关键词] Phosphoenolpyruvate carboxylase;C4 photosynthesis;Phosphorylation;Protein kinase inhibitor;Ca2+-dependent protein kinase;Maize;PEPC;phosphoenolpyruvate carboxylase;PK;protein kinase;A-kinase;cyclic AMP-dependent protein kinase;MLCK;myosin light chain kinase;IC50;concentration required for 50% inhibition